Vertical migration of Haemonchus sp. infectant larvae on Stylosanthes spp. and Brachiaria brizantha (Syn. Urochloa brizantha) cv. Marandu forage

The present work aimed to evaluate the influence of Stylosanthes spp. (Campo Grande© styles) and Brachiaria brizantha cv. Marandu in the vertical migration of Haemonchus spp. infective larvae, in the region of Uberlândia, Minas Gerais. Seeds of Stylosanthes spp. and Brachiaria brizantha cv. Marandu were planted in 50 pots of five liters (20 cm diameter) evenly disposed in an area of the Capim Branco Experimental Farm, Federal University of Uberlândia. When both species reached the minimum height of 20 cm, the pots were experimentally contaminated with sheep feces coprocultures. Samplings were performed, with complete removal of the vegetal material contained in the pots, on days one, three, six, 10 and 14 after contamination. Nematoids were recovered from the plant samples by thermo and hydrotropism, counted under an optical microscope and identified. For statistical analysis, the data were analyzed in a completely randomized design (DIC) in a 2X5 factorial scheme (two fodder species X 5 collection dates). No effect of the forage species was observed on the number of L3 of Haemonchus sp. recovered in the feces (p = 0.7790), upper stratum (p = 0.1755) or lower stratum (p = 0.7883) of the forage, however, there was a significant decrease in the number of L3 found with the passing of the days. When comparing the mean L3 recovered in the upper (0.06±0.31 L3) and lower (2.94±0.39) strata, a higher number of larvae was observed in the lower stratum (p < 0.0001). Therefore, in both forage species studied, the upper stratum of the plants, preferably pastured by the animals, remained with less contamination of infective larvae and the contamination tended to decrease over the days.

Effectiveness of monepantel and levamisole to control gastrointestinal strongylid parasites of sheep / Eficácia de monepantel e levamisol no controle de estrongilídeos parasitos gastrintestinais de ovinos

Anthelmintic resistance poses a major challenge to the control of endoparasites in sheep. The recent launch of monepantel may represent an alternative for the treatment of helminth infections. The purpose of this study was to assess the effectiveness of monepantel and levamisole in the sheep flock on the experimental farm Capim Branco, of the Federal University of Uberlandia, municipality of Uberlandia, state of Minas Gerais, Brazil. Thirty sheep with more than 200 eggs per gram of feces (EPG) were selected. Ten of these animals were treated orally with 2.5 mg/kg of monepantel, ten were treated subcutaneously with 7.5 mg/kg of levamisole, and ten served as control animals. Fecal samples for the determination of EPG were collected on days zero (pre-treatment), seven and fourteen (post-treatment). The percentage of effectiveness was calculated using RESO 2:01 software. Monepantel reduced the EPG of Haemonchus sp. and Trichostrongylus sp. by more than 95%, but Oesophagostomum sp. was reduced by only 50% and 33% on days seven and fourteen. The percentage reduction of EPG by levamisole remained above 95% for all the helminths recovered from fecal cultures, indicating its effectiveness. These data demonstrate the failure of monepantel to control Oesophagostomum spp. in the evaluated sheep flock.

A resistência anti-helmíntica é um dos maiores desafios para o controle de endoparasitos em ovinos. O recente lançamento do monepantel pode representar uma alternativa para o tratamento das helmintoses. Este trabalho objetivou avaliar a eficácia do monepantel e levamisol no rebanho ovino da Fazenda Capim Branco da Universidade Federal de Uberlândia, em Uberlândia, Minas Gerais. Foram selecionados trinta ovinos com valores de ovos por grama de fezes (OPG) superiores a 200. Destes animais, dez foram tratados com monepantel 2,5 mg/kg, via oral, dez receberam tratamento subcutâneo com levamisol 7,5 mg/kg, e os outros 10 permaneceram como animais controle. No dia zero (prétratamento), sete e quatorze (pós-tratamento), realizou-se coletas de fezes para determinação de OPG. O percentual de eficácia foi calculado pelo software RESO 2.01. O monepantel apresentou percentual de redução superior a 95% para Haemonchus sp. e Trichostrongylus sp., porém este percentual para Oesophagostomum sp. foi de 50% e 33%, no sétimo e décimo quarto dia. O percentual de redução de OPG para levamisol se manteve superior a 95% para todos os helmintos recuperados nas coproculturas, indicando sua eficácia. Estes dados indicam a falência do monepantel em realizar o controle de Oesophagostomum spp. no rebanho avaliado.